4790cb5009
Normally the IOR is deduced from the reflectance, but now we allow to specify the IOR instead or in addition to the reflectance. In the later case, it's possible to create physically impossible materials, but this can be useful for artistic reasons.
63 lines
1.8 KiB
GLSL
63 lines
1.8 KiB
GLSL
#if defined(TARGET_MOBILE)
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// min roughness such that (MIN_PERCEPTUAL_ROUGHNESS^4) > 0 in fp16 (i.e. 2^(-14/4), rounded up)
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#define MIN_PERCEPTUAL_ROUGHNESS 0.089
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#define MIN_ROUGHNESS 0.007921
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#else
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#define MIN_PERCEPTUAL_ROUGHNESS 0.045
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#define MIN_ROUGHNESS 0.002025
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#endif
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#define MIN_N_DOT_V 1e-4
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float clampNoV(float NoV) {
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// Neubelt and Pettineo 2013, "Crafting a Next-gen Material Pipeline for The Order: 1886"
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return max(NoV, MIN_N_DOT_V);
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}
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vec3 computeDiffuseColor(const vec4 baseColor, float metallic) {
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return baseColor.rgb * (1.0 - metallic);
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}
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vec3 computeF0(const vec4 baseColor, float metallic, float reflectance) {
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return baseColor.rgb * metallic + (reflectance * (1.0 - metallic));
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}
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float computeDielectricF0(float reflectance) {
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return 0.16 * reflectance * reflectance;
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}
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float computeMetallicFromSpecularColor(const vec3 specularColor) {
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return max3(specularColor);
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}
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float computeRoughnessFromGlossiness(float glossiness) {
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return 1.0 - glossiness;
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}
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float perceptualRoughnessToRoughness(float perceptualRoughness) {
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return perceptualRoughness * perceptualRoughness;
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}
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float roughnessToPerceptualRoughness(float roughness) {
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return sqrt(roughness);
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}
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float iorToF0(float transmittedIor, float incidentIor) {
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return sq((transmittedIor - incidentIor) / (transmittedIor + incidentIor));
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}
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float f0ToIor(float f0) {
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float r = sqrt(f0);
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return (1.0 + r) / (1.0 - r);
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}
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vec3 f0ClearCoatToSurface(const vec3 f0) {
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// Approximation of iorTof0(f0ToIor(f0), 1.5)
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// This assumes that the clear coat layer has an IOR of 1.5
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#if defined(TARGET_MOBILE)
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return saturate(f0 * (f0 * 0.526868 + 0.529324) - 0.0482256);
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#else
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return saturate(f0 * (f0 * (0.941892 - 0.263008 * f0) + 0.346479) - 0.0285998);
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#endif
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}
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